I purchased a 1.5 ton cube split ac of panasonic company fitted in room 10*13 and roof hightis 11 fit , it's copresser is working 3 to 4 hrs continuosly but tempreture of room is not much cool it feeling is not like an ac is on from last 3 to 4 hrs. is there any problem in ac. I would like to know that how much time should take an ac to reach 20 degree c if outer normal temp. is 34 degree .
Kindly help me , did I purchased a wrong company ac or model.

Depending on roof construction, shading,windows, insulation etc it may not cool to 20C(68F-. That's a big drop. Does it cool down at night?